Compression and injection molding are commonly used in various fields to form finished articles of many industrial products, for example, automobile interior panelling.
Panelling parts, in particular those having a reinforcing and a bearing function, are frequently produced as compression molded parts from compressed fibre composites known as sheet molding material. The compressed plastics fibre in such materials are inexpensive and relatively lightweight, which is particularly advantageous in automobile construction. Other elements such as mounting brackets are attached to the compression molded parts. Since such load bearing elements are generally of a more complex shape, and must have greater stability than panelling, they are usually made from a different material through an injection molding process.
Typically, each of the components for a finished piece is molded separately according to its appropriate method, either compression or injection molding. Once each component is formed, they are fitted together to form a finished product. The fastening or mounting elements may be attached to the panel by a variety of methods including adhesives, rivets, welds, interlocking connections, or other means well-known in the art. Attachment therefore involves an additional step in the manufacturing process and additional materials such as adhesives or rivets. Therefore, the overall cost of manufacturing of each finished article is increased.
Generally, the connection between the elements of such a composite product is relatively weak and often fails during use of the finished article, separating the individual components. Although attempts have been made to strengthen the connection between each component on a finished article, they have been largely unsuccessful.
Therefore, there is a need to provide for an apparatus and method of constructing articles including different components made of injection and compression molding to form a strong connection between each of the components and to avoid weak joints.